The field of exercise or therapy devices for the knee and upper leg muscles is and has been an active one, involving various approaches, devices and apparatus permitting repetitive exercises against selective or variable resistances and forces. Exemplary of these are those shown in U.S. Pat. No. 2,855,199 issued Oct. 7, 1958 (Noland et al), U.S. Pat. No. 3,850,430 issued Nov. 26, 1974 (Hamilton), U.S. Pat. No. 4,256,302 issued Mar. 17, 1981 (Keiser et al) and U.S. Pat. No. D. 263,978 issued Apr. 20, 1982 (Brentham). Devices as shown in these patents are useful to greater or lesser extents. However, in general they all follow a similar approach whereby the repetitive exercises involve fixing the femur, and having the quadriceps and hamstrings extend and flex the knee through movement of the foot. While this approach can be beneficial, I consider that it does not properly simulate natural sports activity involving running. Thus, all activities that involve running generally have the foot planted, and the knee moves to accommodate the activity. Therefore, it is a basic concept of my invention that the foot be fixed, and that the quadriceps muscles extend the knee against resistance, while controlled return of the knee to a flexed condition exercises the hamstrings. In devices according to my invention, the femur is not fixed, and thus there is less apparent force on the patella femoral joint. Additionally, devices in accordance with my invention achieve a unique degree of isolation of the quadriceps muscles during use. I know of no device or apparatus in the prior art that possesses the unique features, functions and advantages of devices and apparatus in accordance with my invention.
A primary purpose of my invention is to provide a unique quadriceps strengthening machine that allows strengthening of the quadriceps in a way that is better related to natural sports activity. Machines in accordance with my invention may also be used on many different types of knee pathology, as well as to strengthen knees for the prevention of injuries. Knee problems involving torn menisci, ligamentous instability, and patella problems may be advantageously treated on machines in accordance with my invention as approved by the physician and therapist. Machines in accordance with my invention also are very efficient hip flexor strengtheners, and the hip extensors and the hamstrings can be advantageously worked on to improve their strength. Machines according to my invention, while fairly specialized in their primary purposes, are embodied in preferred embodiments of substantial versatility in other types of exercise. Accordingly, my invention can be characterized not only by its primary purposes, features and concepts, but also by its versatility, simplicity, reliability, and ease of use.
The various aspects and features of my invention will become apparent to those skilled in the art from the ensuing description of presently preferred embodiments, taken in conjunction with the accompanying drawings .